> Is there something special to do for htmlize to process an #+INCLUDE'd
> source file ?

No.

Do you mean that it should work out of the box or that it is not working at all?
Because for me:
- I can htmlize src blocks (with BEGIN_SRC)
- I can highlight src blocks with syntaxhighlighter  (by new-exporting to html)
- I can highlight included src blocks with syntaxhighlighter

Given the fact that '#+INCLUDE: "file" src java' is expanded into an src block,
I assume that htmlize should apply there too. Am I wrong?

Greetings,

Fabrice